Circuit making and breaking mechanism



API'I 4, 1950 w. LEATHERs Erm. 2,502,967

cIRcuI'r mms AND BREAKIN@ MECHANISM Filed D90. 29, 1945 2 Sheet's-Sheetl INVENTORS: WardnghenzZ i- BYau/rncc rmh ATTORNEY April 4, 1950 Y w.LEATHERs ETAL 2,502,967

CIRCUIT MAKING AND BREAKING MECHANISM Filed Deo. .29, 1945 2sheets-sheet 2 Pff 1: fg

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'ATTORNEY Patented Apr. 4, 1950 CIRCUIT MAKING AND BREAKING MECHANISMWard Leathers, Brooklyn, and Lawrence Bruehl, New York, N. Y., assigner;to International Business Machines Corporation, New York, N. Y., acorporation ci New York Y Appumionpmmber 29, 1945, serial No. 638,398

l Claim. 1 p

The improved circuit making and breaking mechanism comprising thepresent invention-is primarily adapted for use in connection with gunstabilization mechanism of the type shown in a cci-pending applicationof Ward Leathers et al., Serial No. 638,394, led December 29, 1945, forStabilized gun control mechanism, of which the present application is acontinuation-impart.

. While the circuit making and breaking mechanism comprising the presentinvention is primarily adapted for use in connection with gunstabilizing mechanism, as outlined above, it will be' understood thatthe same may have numerous other applications in controlling theeiiective speed or speeds of operation of one or more electricallydriven motors. Furthermore, the circuit making and breaking mechanism isnot necessarily limited to controlling electrical motor'circuits andthe-same may, if desired, with or without modiiication, be employed forselectively energizing or deenergizing any electrical circuit or Vanynumber of circuits for varying lengths of time during each cam cycle orfor operating upon one or'more pairs of electrical contacts to open andclose the same, regardless of the nature to which these electricalcircuits or contacts may be put'.

The provision of a circuit making and breaking apparatus of thecharacter briefly outlined above being the principal object of theinvention, other objects and advantages thereof will become ap-v parentas the nature of the invention is better vmderstood.

In the accompanying two sheets of drawings forming a part of thisspecification:

Fig. 1 is a tcp plan view of the improved circuit maker and breakermechanism.

Fig. 2 is a side elevational view thereof.

Fig. 3 is a sectional view taken substantially along the line 3-3 ofFig. 1.

Fig 4 is an electrical circuit diagram showing the electricalconnections for the circuit maker and breaker mechanismwhen employed inconnection with gun-stabilizing mechanism;

The circuit making and breaking mechanism shown in detail in Figs. 1 and2 is employed for the purpose of selectively applying current imthestructure and nature of which will be made clear presently.

The motors Mt and Me are substantially identical in construction andeach is preferably in the form of a reversible direct current motorhaving a ground connection and eld winding connections represented bythe wires a and b. 'Ihe reversible circuit for the motor Mt leads fromthe ground g, battery B, through wire c, resistance RI, coil or pigtaillead wire d, a pair of cooperating contacts CI, a slidable contact C2,and one orthe other of a pair of contact bars III or I2, as the case maybe, leading to the wires a and b respectively and from thence throughthe motor windings to ground g. The contacts CI and C2 are suitablycarried upon a sliding member Il which is movable in opposite directionsin such a manner that the contact C2 may engage one or the other of thecontact bars I0 or I2. When the member I4 is in its neutral or centerposition, the Contact C2 rests upon an insulation strip I6 whichseparates the bars I0 and I2 so that no current may ow through themotor.

With either of the circuits above described in effect, it will be seenthat on account of the resistance RI, which is preferably of a low ohmicvalue in the neighborhood of ten ohms, somewhat pulses to the motors Mtand Me at regular cyclic intervals and for varying periods or incrementsof time ranging from no impulses whatsoever, i.

e. impulses o f zero duration, to the continuous application "of directcurrent to the motors, i. e. impulses of infinite duration. Controlswhich make this possible for each motor are entirely independent ofeachother but are in common dependent uporr the provision of a rotarycam,

less than the full rated voltage of the battery B is applied to themotor for rotation thereof in either direction when the contact C2 issolely in engagement with either of the contact bars I0 or I2. Means areprovided, however, that when the member I4 is moved to either of itsextreme positions a branch circuit is established, the net effect ofwhich is to place an additional resistance R2 in the circuit in parallelwith the resistance RI, so that the value of voltage applied to themotor may more nearly approach the full rated voltage of the battery.This lattter feature is accomplished by the provision of a pair ofcontact bars I8 and 20 which are positioned adjacent the ends of theContact bars I0 and I2 respectively and are separated therefrom byinsulation pieces 22 and 24. It will be seen that when the member I 4 ismoved to one extreme position, the sliding contact C2 will bridge thecontact bars I0 and I8, thus allowing current to ilow through anadditional path leading from ground g through battery B, Wire h,resistance R2, wires i, e, contact bar I8, contact C2, contact bar I 0and wire a to the motor. The contact bars I8 and 2U are connected incommon by a wire f, and thus a similar circuit prevails when the memberI4 is moved to its other extreme position.

The contacts CI are designed for cooperation 3 with a rotary cam member26, the nature of which will be made clear presently. For the present,it

is deemed suillcient to state that this member isy generally ofelongated cylindrical design and the surface thereof is so constructedthat when the contacts CI assume their neutral or center position theywill remain at all times open despite the rotation of the cam member 26.As the contacts Cl are shifted away from their neutral position towardeither end of the cam member 26, means are provided whereby the contactsCl are caused to become closed intermittently for correspondingly longerand longer periods of time until such time as these contacts assume oneor the other of their extreme positions, at which time the contacts CIwill remain permanently closed, thus supplying a steady direct currentflow to the motor at the highest possible voltage attainable from thebattery B through the resistance RI and R2 in parallel. During all othertimes until the contacts reach either of these extreme positions, theintermittent current impulses applied to the motor will be at somewhatlesser voltage since only the resistance RI will exist in the motorcircuit.

The electrical arrangement described above constitutes the circuitcontrol for the motor Mt by means of which, in the gun stabilizingmechanism of the above mentioned co-pending application, stabilizationof the turret in azimuth is effected. A similar circuitarrangementexists for the motor Me by means of which the gun is stabilized inelevation. It is deemed unnecessary to enter into detailed descriptionof the circuit arrangement for the motor Me, it being suicient to applysimilar and corresponding reference characters to the various circuitparts and elements. A pair of cut-out contacts C3 and C4 are disposed inthe circuit of the motor Me and are adapted to become open when the gunreaches either limit of its elevational movements. The manner in whichthese contacts operate has been disclosed in the above mentionedapplication and it is deemedsuicient to state herein that one of thesecontacts will become open when the gun is elevated at an angle ofapproximately 30 and that the other contact becomes open when the gun islowered from the horizontal at an angle of approximately The cam member26 is adapted to be driven through a gear reduction device 28 from amotor M which is designed to operate at a continuous rate of speed andby means of which the cam member 26 is caused to perform one cycle inapproximately one-thirtieth of a second, although it is obvious thatvarious other lengths of time may be selected for the cam cycle. Thearrangement of parts thus far described has been concerned primarilywith the control of the eective speed of rotation vof the traverse motorM. A similar set of instrumentalities is provided and is associated withthe cam member 26 for controlling the eiective speedof rotation of themotor Me. This mechanism is substantially a duplication of thepreviously 'described mechanism and the circuits involved aresubstantially identical.

Referring now to Figs. l, 2 and 3, the circuit making and breakingapparatus per se is designated in its entirety at 30 and is mounted upona base plate 32. The base plate 32 is centrally carried upon a secondbase plate 34, thisilatter plate being provided for the purpose ofsupporting various motor drive, gear reduction and control handlemechanisms for actuating the circuit making and breaking mechanism 30.

Extending longitudinally of the base plate a2 and projecting upwardlytherefrom and substantially coextensive therewith is a block member 36.The ends of the block 36 are formed with upwardly projecting roundedears 38 which serve to rotatably support therein the opposite ends of ashaft 40 on which there is pinned as at 42 the previously mentioned cammember 26. One end of the shaft 40 projects outwardly beyond theconfines of the ears 38 and carries thereon a gear 44 which forms oneelement of the gear reduction device 28. The gear reduction device 28 issuitably supported on a standard 46 which is secured as at 48 to thebase plate 34 and which projects upwardly therefrom. The casing 56 ofthe motor M is bolted or otherwise secured to the standard 46 and isprovided with a driving shaft 54 which projects through an opening inthe standard 46 and thus operatively communiing purposes.

The contacts Ci, which control the movements of the motor Mt, areassociated with one specic set of contactinstrumentalities existing onone side of the block .36 and which operate under the control of ahandle 56. The contacts Cl' are associated with an identical set ofcontact instrumentalities operating under the control of a similarhandle 56. Since these two sets of contact instrumentalities areidentical in construction, a description of one of them will sumce forthe other and, accordingly, the set of instrumentalities associated withthe contacts Ci, which control the movements of the traverse stabilizingmotor Mt, will be described and similar reference'characters will beapplied to the corresponding parts of the other set ofinstrumentalities.

The block member 36 is provided with a slot 56 in each side thereof anda pair of elongated strips of material 60 are fastened by means ofcountersunk studs 62 to each side of the block and have their edgesoverlying the slots 53, thus forming on opposite sides of the block apair of guideways 64. Slidably supported in the guideway 64 is a slidemember 66 of a thickness slightly greater than the depth of the slot 58and which, as a consequence, projects outwardly from this slot. Theouter surface of the slide member 66 has secured thereto an upstandingspring member 68. The member 68 is generally of triangular configurationand carries at its upper end a cam finger 10 designed for cooperationwith the surface of the cam 26. The slide member 66 also has mountedthereon a contact assembly 'l2 including the pair of contacts Cl. Oneelement 'i4 of the pair of contacts CI is mounted on a contact strip 16,the lower end of which is turned outwardly as at 18 and provides asliding contact element 86 designed for cooperation with a contact barB2 mounted on an elongated insulation bar 84 suitably secured to thebase plate 32. The other element 88 of the contacts Ci is mounted on acontact strip 90, the lower end of which is in electrical engagementwith a wiper arm 92 carrying the sliding contact element C2 designed forselective engagement with the pair of contact bars I6 and i2 or forengagement with the insulation strip I6. The contact bars 82, lllv andI2 are provided with respective binding posts 96.` 98 and IUIJ.

It is to be noted that whereas in Figs. 1, 2 and 3 the contact element14 of the pair of contacts CI makes electrical contact with its bindingpost 96 through the contact strip 16 and contact bar 82, in Fig. 4 thiscontact element 'I4 has assoelated therewith the flexible coil orpigtail lead wire d. The two structures are equivalent elecytxically andfor simplicitys sake the simpler form has been employed in the circuitdiagram.

The rotary cam member 26 is of elongated, generally cylindrical designand is truly cylindrical in its exact medial regions throughout a limitband or extent designated at |02. The cam member 26 is provided withopposed raised portions |06 and |06 which are symmetrical and whichtaper from substantially aV point in the vicinity of the medial regions|02 outwardly toward the opposite ends of the member and ilnallyterminate in cylindrical portions |06 at the ends of the member.

From the above description it will be seen that when the slide member 66is in its center position during rotation of the cam member and, as avconsequence, the contact elements 16 and 66 of the pair of contacts CIwill remain electrically apart. In additionto this, the wiper arm 92will be so positioned `that the sliding contact C2 rests upon theinsulation strip I6 so that no circuit through the contacts CI is madepossible. `As the slide member 66 is moved in one direction or the otheraway from its medial position, the cam linger I will move into thepathof movement of one or the other of the raised cam portions l06 or |06,as the case may be. In the initial stages of displacement each time oneor the other of the raised cam surfaces I 66 or |06 engages the camlinger 10, a momentary closingv of very brief duration of the contactsCI will result. As the slide member 66 becomes further displaced fromits medial position, the duration of closing of the contacts CI willbecome correspondingly increased, although the time of closing in thecam cycle will not be altered. As the slide member 66 approaches eitherlimit at one or the other end of the cam member 26, the duration ofclosing of the contacts CI will be comparatively long for each cycle.Finally, when the' slide member 66 attains one or the other of itsextreme positions, the cam ilnger will ride onto one or the other of thecylindrical portions |66 of the cam 26 and the contacts CI will thenremain vcontinuously closed.

In order to move the slide member 66 in one direction or the other, thesame is formed with While there have been shown and described andpointed out the fundamental novel features of the invention as appliedto a preferred embodiment, it will be understood that various omissionsand substitutions and changes in the form and details of the apparatusillustrated and in its operation may be made by those skilled in the artwithout departing from the spirit of the invention. It is the intention,therefore, to be limited only as indicated by the scope of the followingclaim.

What is claimed is:

Circuit making and breaking apparatus of the character describedcomprising in combination a supporting block, a pair of supportingmemberslmovable therein axially of the cam' member, a

pair of contact arms mounted on said slide member and projectingupwardly therefrom, a pair of normally open cooperating contacts carriedby said arms, a contact finger mounted on one of thereof between whichthere extends one end of a link I I2, theears and link being suitablypinned together as at' Ill. 'I'he free or outer end of the link H2 ispivoted asiat II6 to one end oi' the control handle I6, this latterhandle being' pivoted .as at II6 to the base plate 66. Itwill be seenthat as the handle 66 is swung to the right or 'to the left. as viewedin Fig. 1, the slide member 66 will be moved in the opposite directionto vary the duration of closing movements oi' the contacts CI. as wellas to vary the direction of ciment ilow through the motor Mt.

Itisalsotobenotedthatthetwosetsofinstrumentalities which operate underthe control of the handles 66 and 66' operate entirely inde- .pendentlyof eachother, one serving to control thel motion of the motor Mt and theother serving tocontrol the motion of the motor Alle.

saidaarms and'at all time's yieldingly engaging the surface of said cammember in any position of adjustment of the slide member, a stationarycontact bar substantially coextensive with the cam member, a wiper armbearing against said bar and electrically connected to one of saidcontact arms, an additional pair of contact bars arranged in alignment,an insulated medium separating all of said contact bars from each other,a second wiper arm electrically connected to the other contact anddesigned for -selectively engaging either of said latter pair of contactbars upon shifting of the slide member, a pair of cam proiections formedon the surface of said cam member and controlling the opening andclosing movements of said contacts, said cam projections in the vicinityof the end regions of the cam member being continuous and extendingcompletely around the surface of the cam member and progressivelydecreasing in extent inwardly ofthe cam member and thus tapering; to ,apoint in the vicinity of the regions of the rcam member, said cam fingernormally occupying a position intermediate said cam projections, andsaid last mentioned wiper arm occupying a position intermediate saidpair of contact bars when the slide member is in its central position,and ,means for shifting said slide member axially ,of

the cam member.

WARD LEATHERS. LAWRENCE BRUEHL.

REFERENCES CITED ille of this patent:

UNITED STATES PATENTS Number Name" Date 1,481,001 Hartford July 3. 19381,971,313 Johnson Aug. 21, 1934 2,100,776 Johnson Mar. 1, 1938

